Radio frequency (RF) controlled lamp with dimmer compatibility

ABSTRACT

An RF controlled lighting unit is provided, suitable for connection to at least one of a dimmer for adjusting a phase cut angle of input mains voltage in accordance with an adjustable dimming level or an electronic switch for selecting between on- and off-states. The lighting unit includes a solid state light source; a radio circuit for receiving a wireless control signal; a rectifier circuit for rectifying the input mains voltage received from the electronic switch or the dimmer; a first power converter for driving the solid state light source in response to the rectified input mains voltage and delivering power to the radio circuit; and a second power convertor for delivering power to the radio circuit when the rectified input mains voltage becomes inadequate for the first power converter due to the phase-cut angle of the rectified input mains voltage or the off-state of the electronic switch.

TECHNICAL FIELD

The present invention is directed generally to control of solid statelighting fixtures. More particularly, various inventive devices andmethods disclosed herein relate to remotely controlling a lamp withdimmer compatibility.

BACKGROUND

Digital or solid state lighting technologies, i.e., illumination basedon semiconductor light sources, such as light-emitting diodes (LEDs),offer a viable alternative to traditional fluorescent, high-intensitydischarge (HID), and incandescent lamps. Functional advantages andbenefits of LEDs include high energy conversion and optical efficiency,durability, lower operating costs, and many others. Recent advances inLED technology have provided efficient and robust full-spectrum lightingsources that enable a variety of lighting effects in many applications.

Some of the fixtures embodying these sources feature a lighting unit,including one or more LEDs capable of producing white light and/ordifferent colors of light, e.g., red, green and blue, as well as acontroller or processor for independently controlling the output of theLEDs in order to generate a variety of colors and color-changinglighting effects, for example, as discussed in detail in U.S. Pat. Nos.6,016,038 and 6,211,626, incorporated herein by reference. LEDtechnology includes line voltage powered white lighting fixtures, suchas the EssentialWhite™, available from Philips Color Kinetics.EssentialWhite™ may be dimmable using trailing edge dimmer technology,such as electric low voltage (ELV) type dimmers for 220 VAC linevoltages (or input mains voltages).

Many lighting applications make use of dimmers. Conventional dimmerswork well with incandescent (bulb and halogen) lamps. However, problemsoccur with other types of electronic lamps, including compactfluorescent lamp (CFL), low voltage halogen lamps using electronictransformers and solid state lighting (SSL) lamps, such as LEDs andOLEDs. Low voltage halogen lamps using electronic transformers, inparticular, may be dimmed using special dimmers, such as ELV typedimmers or resistive-capacitive (RC) dimmers, which work adequately withloads that have a power factor correction (PFC) circuit at the input.

Conventional dimmers typically chop a portion of each waveform of theinput mains voltage signal and pass the remainder of the waveform to thelighting fixture. A leading edge or forward-phase dimmer chops theleading edge of the voltage signal waveform. A trailing edge orreverse-phase dimmer chops the trailing edges of the voltage signalwaveforms. Electronic loads, such as LED drivers, typically operatebetter with trailing edge dimmers. Unlike incandescent and otherresistive lighting devices which respond naturally without error to achopped sine wave produced by a phase chopping dimmer, LEDs and othersolid state lighting loads may incur a number of problems when placed onsuch phase chopping dimmers, such as low end drop out, triac misfiring,minimum load issues, high end flicker, and large steps in light output.

Radio or radio frequency (RF) controlled lighting units generallyinclude onboard radio transceivers or modems, and are often referred toas “connected lamps,” such as the Philips Hue. However connected lampsdo not always work well in combination with wall dimmers or electronicswitches. Such electronic switches are used, for example, in varioussensors that enable automatic operation of the lighting units, includingdaylight sensors, presence/occupancy detectors, or remotely controlledswitches, such as in the ClickOnClickOff (COCO) portfolio, for example.In the future, when multiple control systems need to work together(e.g., radio controlled lamps plus building management systems thatswitch groups of light sockets), electronic switches may become morecommon.

Most consumer lighting controllers are two-wire devices. A problemtherefore arises when a dimmer or electronic switch interrupts just oneof the two wires, as discussed below. In fact, most consumer lightingcontrollers are two-wire devices that only interrupt the live wire. Inthis configuration there is no neutral connection to the lightingcontroller that would enable the off-state current to run through thelighting unit(s). An off-state bleeder may be included to ensure thatthe lighting unit does not flicker or glow when the dimmer is switchedoff. In case, however, the RF radio (transceiver or modem) in aconventional radio control lighting device is no longer functional, as apractical matter, when the dimmer or switch is in off-state.

A lighting unit controlled by a two-wire device, for example, works wellwhen the lamp appears as a low impedance load, as in the case of anincandescent lamp. The lamp must provide a current path to keep thedimmer or switch in operation. When the lamp comprises an LED lamp,though, the load may be so high-impedance that even with the very smallremaining leakage current through the switch, the lamp can start to emit(some) light and boot software running on its internal microcontroller.This behavior leaks to visible glowing or flickering, and is undesiredwhen the dimmer or electronic switch is set in an off-state.

To prevent this undesirable operation, a conventional LED lamp mayinclude an “off-state bleeder,” which is a small electronic circuitconnected in parallel with the LED lamp. The off-state bleeder ensuresthat there is always enough current floating such that the dimmer orswitch may continue to function, and that the LED lamp remains off whenthe dimmer or electronic switch is in the off-state. This configurationresolves the problem by provide flow of a small current when theelectronic switch or lamp is in the off-state.

However, the connected lamp may draw too little power to let thiscurrent flow. If the dimmer or electronic switch no longer functions asa result, it may fail to switch on again. Also, the connected lamp seessome power on its mains power line connector, and may try to boot up.The connected lamp may flicker during this attempt, which may beannoying to the user.

Thus, there is a need in the art to detect improper operation oflighting system components, such as the dimmer and/or the solid statelighting load driver, and to identify and implement corrective action tocorrect the improper operation and/or remove power to the solid statelighting load, to eliminate undesirable effects, such as light flicker.

SUMMARY

The present disclosure is directed to inventive devices and methods fora radio in an RF controlled lighting unit that remains functional duringvery low dimming state of a dimmer (low phase cut angle of rectifiedinput mains voltage) and/or an off-state of the dimmer or an electronicswitch, via a modified bleeder circuit that extracts power from ableeder circuit to continue to provide power to a transceiver andmicroprocessor of the radio. This also enables new features to makeinteraction more user friendly.

Generally, in one aspect, a radio frequency (RF) controlled lightingunit is provided, suitable for connection to at least one of a dimmerconfigured to adjust a phase cut angle of an input mains voltage frommains in accordance with an adjustable dimming level or an electronicswitch configured to provide selection between an on-state and anoff-state. The lighting unit includes a solid state light source; aradio circuit configured to receive a wireless control signal, enablingcontrol of the lighting unit; a rectifier circuit configured to rectifythe input mains voltage received from the dimmer or the electronicswitch; a first power converter configured to drive the solid statelight source in response to the rectified input mains voltage and todeliver power to the radio circuit; and a second power convertorconfigured to deliver power to the radio circuit when the rectifiedinput mains voltage becomes inadequate for the first power converter dueto the phase-cut angle of the rectified input mains voltage or theoff-state of the electronic switch.

In another aspect, a method is provided for remotely controlling alighting unit configured to adjust a phase cut angle of an input mainsvoltage from mains in accordance with at least one of an adjustabledimming level or an electronic switch configured to provide selectionbetween an on-state and an off-state. The method includes connecting aresistive bleeder circuit in parallel with a light emitting diode (LED)light source of the lighting unit, the resistive bleeder circuitapplying a resistive load to the dimmer when the input mains voltagebecomes inadequate to drive the LED light source due to the phase-cutangle or the off-state of the input mains voltage; extracting power fromthe resistive bleeder circuit for powering a radio circuit when theresistive bleeder circuit is connected in parallel with the LED lightsource; and receiving a control signal wirelessly at the radio circuitwhen the radio circuit is powered by the power extracted from theresistive bleeder circuit, the control signal indicating a desiredlighting level of the LED light source.

As used herein for purposes of the present disclosure, the term “LED”should be understood to include any electroluminescent diode or othertype of carrier injection/junction-based system that is capable ofgenerating radiation in response to an electric signal. Thus, the termLED includes, but is not limited to, various semiconductor-basedstructures that emit light in response to current, light emittingpolymers, organic light emitting diodes (OLEDs), electroluminescentstrips, and the like. In particular, the term LED refers to lightemitting diodes of all types (including semi-conductor and organic lightemitting diodes) that may be configured to generate radiation in one ormore of the infrared spectrum, ultraviolet spectrum, and variousportions of the visible spectrum (generally including radiationwavelengths from approximately 400 nanometers to approximately 700nanometers). Some examples of LEDs include, but are not limited to,various types of infrared LEDs, ultraviolet LEDs, red LEDs, blue LEDs,green LEDs, yellow LEDs, amber LEDs, orange LEDs, and white LEDs(discussed further below). It also should be appreciated that LEDs maybe configured and/or controlled to generate radiation having variousbandwidths (e.g., full widths at half maximum, or FWHM) for a givenspectrum (e.g., narrow bandwidth, broad bandwidth), and a variety ofdominant wavelengths within a given general color categorization.

For example, one implementation of an LED configured to generateessentially white light (e.g., LED white lighting fixture) may include anumber of dies which respectively emit different spectra ofelectroluminescence that, in combination, mix to form essentially whitelight. In another implementation, an LED white lighting fixture may beassociated with a phosphor material that converts electroluminescencehaving a first spectrum to a different second spectrum. In one exampleof this implementation, electroluminescence having a relatively shortwavelength and narrow bandwidth spectrum “pumps” the phosphor material,which in turn radiates longer wavelength radiation having a somewhatbroader spectrum.

It should also be understood that the term LED does not limit thephysical and/or electrical package type of an LED. For example, asdiscussed above, an LED may refer to a single light emitting devicehaving multiple dies that are configured to respectively emit differentspectra of radiation (e.g., that may or may not be individuallycontrollable). Also, an LED may be associated with a phosphor that isconsidered as an integral part of the LED (e.g., some types of whitelight LEDs). In general, the term LED may refer to packaged LEDs,non-packaged LEDs, surface mount LEDs, chip-on-board LEDs, T-packagemount LEDs, radial package LEDs, power package LEDs, LEDs including sometype of encasement and/or optical element (e.g., a diffusing lens), etc.

The term “light source” should be understood to refer to any one or moreof a variety of radiation sources, including, but not limited to,LED-based sources (including one or more LEDs as defined above),incandescent sources (e.g., filament lamps, halogen lamps), fluorescentsources, phosphorescent sources, high-intensity discharge sources (e.g.,sodium vapor, mercury vapor, and metal halide lamps), lasers, othertypes of electroluminescent sources, pyro-luminescent sources (e.g.,flames), candle-luminescent sources (e.g., gas mantles, carbon arcradiation sources), photo-luminescent sources (e.g., gaseous dischargesources), cathode luminescent sources using electronic satiation,galvano-luminescent sources, crystallo-luminescent sources,kine-luminescent sources, thermo-luminescent sources, triboluminescentsources, sonoluminescent sources, radioluminescent sources, andluminescent polymers.

A given light source may be configured to generate electromagneticradiation within the visible spectrum, outside the visible spectrum, ora combination of both. Hence, the terms “light” and “radiation” are usedinterchangeably herein. Additionally, a light source may include as anintegral component one or more filters (e.g., color filters), lenses, orother optical components. Also, it should be understood that lightsources may be configured for a variety of applications, including, butnot limited to, indication, display, and/or illumination. An“illumination source” is a light source that is particularly configuredto generate radiation having a sufficient intensity to effectivelyilluminate an interior or exterior space. In this context, “sufficientintensity” refers to sufficient radiant power in the visible spectrumgenerated in the space or environment (the unit “lumens” often isemployed to represent the total light output from a light source in alldirections, in terms of radiant power or “luminous flux”) to provideambient illumination (i.e., light that may be perceived indirectly andthat may be, for example, reflected off of one or more of a variety ofintervening surfaces before being perceived in whole or in part).

The term “lighting fixture” is used herein to refer to an implementationor arrangement of one or more lighting units in a particular formfactor, assembly, or package. The term “lighting unit” is used herein torefer to an apparatus including one or more light sources of same ordifferent types. A given lighting unit may have any one of a variety ofmounting arrangements for the light source(s), enclosure/housingarrangements and shapes, and/or electrical and mechanical connectionconfigurations. Additionally, a given lighting unit optionally may beassociated with (e.g., include, be coupled to and/or packaged togetherwith) various other components (e.g., control circuitry) relating to theoperation of the light source(s). An “LED-based lighting unit” refers toa lighting unit that includes one or more LED-based light sources asdiscussed above, alone or in combination with other non LED-based lightsources. A “multi-channel” lighting unit refers to an LED-based or nonLED-based lighting unit that includes at least two light sourcesconfigured to respectively generate different spectrums of radiation,wherein each different source spectrum may be referred to as a “channel”of the multi-channel lighting unit.

The term “controller” is used herein generally to describe variousapparatus relating to the operation of one or more light sources. Acontroller can be implemented in numerous ways (e.g., such as withdedicated hardware) to perform various functions discussed herein. A“processor” is one example of a controller which employs one or moremicroprocessors that may be programmed using software (e.g., microcode)to perform various functions discussed herein. A controller may beimplemented with or without employing a processor, and also may beimplemented as a combination of dedicated hardware to perform somefunctions and a processor (e.g., one or more programmed microprocessorsand associated circuitry) to perform other functions. Examples ofcontroller components that may be employed in various embodiments of thepresent disclosure include, but are not limited to, conventionalmicroprocessors, microcontrollers, application specific integratedcircuits (ASICs), and field-programmable gate arrays (FPGAs).

In various implementations, a processor and/or controller may beassociated with one or more storage media (generically referred toherein as “memory,” e.g., volatile and non-volatile computer memory suchas random-access memory (RAM), read-only memory (ROM), programmableread-only memory (PROM), electrically programmable read-only memory(EPROM), electrically erasable and programmable read only memory(EEPROM), universal serial bus (USB) drive, floppy disks, compact disks,optical disks, magnetic tape, etc.). In some implementations, thestorage media may be encoded with one or more programs that, whenexecuted on one or more processors and/or controllers, perform at leastsome of the functions discussed herein. Various storage media may befixed within a processor or controller or may be transportable, suchthat the one or more programs stored thereon can be loaded into aprocessor or controller so as to implement various aspects of thepresent invention discussed herein. The terms “program” or “computerprogram” are used herein in a generic sense to refer to any type ofcomputer code (e.g., software or microcode) that can be employed toprogram one or more processors or controllers.

In one network implementation, one or more devices coupled to a networkmay serve as a controller for one or more other devices coupled to thenetwork (e.g., in a master/slave relationship). In anotherimplementation, a networked environment may include one or morededicated controllers that are configured to control one or more of thedevices coupled to the network. Generally, multiple devices coupled tothe network each may have access to data that is present on thecommunications medium or media; however, a given device may be“addressable” in that it is configured to selectively exchange data with(i.e., receive data from and/or transmit data to) the network, based,for example, on one or more particular identifiers (e.g., “addresses”)assigned to it.

The term “network” as used herein refers to any interconnection of twoor more devices (including controllers or processors) that facilitatesthe transport of information (e.g. for device control, data storage,data exchange, etc.) between any two or more devices and/or amongmultiple devices coupled to the network. As should be readilyappreciated, various implementations of networks suitable forinterconnecting multiple devices may include any of a variety of networktopologies and employ any of a variety of communication protocols.Additionally, in various networks according to the present disclosure,any one connection between two devices may represent a dedicatedconnection between the two systems, or alternatively a non-dedicatedconnection. In addition to carrying information intended for the twodevices, such a non-dedicated connection may carry information notnecessarily intended for either of the two devices (e.g., an opennetwork connection). Furthermore, it should be readily appreciated thatvarious networks of devices as discussed herein may employ one or morewireless, wire/cable, and/or fiber optic links to facilitate informationtransport throughout the network.

It should be appreciated that all combinations of the foregoing conceptsand additional concepts discussed in greater detail below (provided suchconcepts are not mutually inconsistent) are contemplated as being partof the inventive subject matter disclosed herein. In particular, allcombinations of claimed subject matter appearing at the end of thisdisclosure are contemplated as being part of the inventive subjectmatter disclosed herein. It should also be appreciated that terminologyexplicitly employed herein that also may appear in any disclosureincorporated by reference should be accorded a meaning most consistentwith the particular concepts disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameor similar parts throughout the different views. Also, the drawings arenot necessarily to scale, emphasis instead generally being placed uponillustrating the principles of the invention.

FIG. 1 is a block diagram showing a radio frequency (RF) controlledlighting system, according to a representative embodiment.

FIG. 1a is a block diagram showing an electronic switch of an RFcontrolled lighting system, according to a representative embodiment.

FIG. 2 is a block diagram showing a power extractor of the RF controlledlighting system of FIG. 1, according to a representative embodiment.

FIGS. 3A to 3E are block diagrams showing second power convertors of theRF controlled lighting system of FIG. 1, including different resistivebleeder circuits used in conjunction with the power extractor, accordingto representative embodiments.

FIG. 4 is a block diagram showing an RF controlled lighting system, inwhich power supplied from a resistive bleeder circuit is combined withpower from another power supply, according to a representativeembodiment.

FIG. 5 is a block diagram showing an RF controlled lighting system,according to another representative embodiment.

FIG. 6 is a flow diagram showing a process of operating an RF controlledlighting system, according to a representative embodiment.

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation andnot limitation, representative embodiments disclosing specific detailsare set forth in order to provide a thorough understanding of thepresent teachings. However, it will be apparent to one having ordinaryskill in the art having had the benefit of the present disclosure thatother embodiments according to the present teachings that depart fromthe specific details disclosed herein remain within the scope of theappended claims. Moreover, descriptions of well-known apparatuses andmethods may be omitted so as to not obscure the description of therepresentative embodiments. Such methods and apparatuses are clearlywithin the scope of the present teachings.

Generally, it is desirable for a user or sensor to be able to switch ona radio controlled lighting unit when a dimmer and/or an electronicswitch otherwise controlling the lighting unit is otherwise providinginadequate power, for example, when the dimmer is in a very low dimmingstate and/or when the dimmer or the electronic switch is in an off-state(or nearly off-state, as discussed below). Applicants have recognizedand appreciated that it would be beneficial to provide a circuit thatremains powered by a bleed current, so that it is capable of receivingand responding to commands when the dimmer or electronic switch is inthe low dimming or off-state, such as switching on the lighting unit ornotifying the user via a transmitted message that it is unable to switchon the lighting unit due to the dimmer or electronic switch being in thelow dimming or off-state when the user or sensor attempts to switch onthe lighting unit via a radio signal. Generally, according to variousembodiments, an off-state resistive bleeder circuit is modified toprovide a bias supply for the radio circuit to enable continued wirelesscommunication with the user or sensor, while still providing steadylight output from the lighting unit, e.g., without flicker oruncontrolled fluctuation in output light levels, regardless of dimmersettings.

In view of the foregoing, various embodiments and implementations of thepresent invention are directed to a radio frequency (RF) controlledlighting unit (or lamp), connectable to a dimmer configured to adjust aphase cut angle of an input mains voltage from mains in accordance withat least one of an adjustable dimming level and/or an electronic switchconfigured to provided selection between an on-state and an off-state,capable of operating when the phase cut angle is very low or the dimmerand/or the electronic switch is in the off-state.

FIG. 1 is a block diagram showing a radio frequency (RF) controlledlighting system, according to a representative embodiment.

Referring to FIG. 1, RF controlled lighting system 100 includes dimmer105 and RF controlled lighting unit 110 (lamp), where the dimmer 105 isconfigured to adjust a phase cut angle of an unrectified input mainsvoltage from voltage mains 101 in accordance with an adjustable dimminglevel. The voltage mains 101 may provide different unrectified inputmains voltage values, such as 100 VAC, 120 VAC, 230 VAC and 277 VAC,according to various implementations. The dimmer 105 may be a phasechopping dimmer, for example, which provides dimming capability bychopping trailing edges (trailing edge dimmer) or leading edges (leadingedge dimmer) of voltage signal waveforms from the voltage mains 101 inresponse to manual operation of a slider or knob, for example.

In various embodiments, the dimmer 105 may also be operated remotely,for example, in response to wireless dimming control signals receivedfrom a remote control device and/or a sensor (e.g., an occupancysensor). In order to be operated remotely, the dimmer 105 would requirea wireless receiver or transceiver configured to receive, demodulate andprocess the wireless dimming control signals and a controller configuredto electronically control operation of the dimmer 105 in response to theprocessed control signals, as would be apparent to one of skill in theart. In an example, the remote control device may be a hand held RFtransmitter, such as a smart phone, in which remote control functionsare presented to the user in the form of an application (“app”).Alternatively, the remote control device may be a dedicated transmittingdevice, e.g., for line-of-sight communication, to operate the dimmer 105specifically and/or the RF controlled lighting system 100 generally.Reception of the wireless control signal from the remote control devicemay occur via a bridge or a router (not shown) that relays the wirelesscontrol signal, and translates the wireless control signal from onestandard to another. For example, the bridge or the router may translatethe wireless control signal between various standards, such astranslating between Wi-Fi (IEEE 802.11) with HyperText Markup Language(HTML) commands and ZigBee Light Link commands.

An electronic switch may be included in place of or in addition to thedimmer 105, where the electronic switch provides selection between an“on-state” and an “off-state.” FIG. 1a is a block diagram showing anelectronic switch of an RF controlled lighting system, according to arepresentative embodiment.

Referring to FIG. 1a , electronic switch 105 a is characterized by amechanical or solid state (e.g. triac) switch 1053 that is controlledelectronically by a controller 1052. The controller 1056 needs a powersupply 1051 that is fed via the wires 1055 and 1056. Here, off-state mayrefer to a state that allows a small amount of current leakage,typically via wires 1055 and 1056 and the power supply 1051, or as aleakage though the solid state switch 1053 (as opposed completedisconnection from the power source), which enables the electronicswitch 105 a, and in particular controller 1052, to continue functioningat a low level. For example, the current leakage feeds the power supply1051, which enables the electronic switch 105 a to react to anobservation by sensor 1054, for example, by entering the on-state fromthe off-state.

In various configurations, the dimmer 105 in FIG. 1 may include a fullydimmed setting which corresponds to an off-state of an electronicswitch, such as the electronic switch 105 a. To a large extent, issuesand solutions for the dimmer 105 and the electronic switch 105 a aresubstantially the same. For example, off-state leakage currents (e.g.through the power supply 1051, and the wires 1055 and 1056) may causelight emitting diodes (LEDs), such as LEDs 141 to 143 of solid statelight source 140) to glow or flicker, which requires counter measures.On the other hand, such current may allow a radio circuit 160 in the RFcontrolled lighting unit 110 to receive enough power for some basicoperations, as discussed below. The radio circuit 160 may beimplemented, for example, as a simple radio consisting of at leastantenna and radio frequency oscillator element and/or a radio integratedcircuit (IC), or the like.

In various embodiments, the electronic switch 105 a also may be operatedremotely, for example, in response to wireless switch control signalsreceived from a remote control device and/or a sensor (e.g., sensor1055). As discussed above with regard to the dimmer 105, in order to beoperated remotely, the electronic switch 105 a would require a wirelessreceiver (or transceiver) configured to receive, demodulate and processthe wireless switch control signals and a controller configured tocontrol operation of the electronic switch 105 a in response to theprocessed control signals, as would be apparent to one of skill in theart.

Referring again to FIG. 1, the RF controlled lighting unit 110 receivesunrectified (AC) voltage from voltage mains 101, which may be dimmed orundimmed, e.g., depending on circuit configuration and/or the phase cutangle setting (i.e., dimmer setting) of the dimmer 105. The RFcontrolled lighting unit 110 includes rectification circuit 120, firstpower converter 130, solid state light source 140, second powerconverter 150 and the radio circuit 160. The rectifier 120 may contain afull-bridge rectifier (e.g., four diodes), but not a storage capacitorto smooth the DC voltage. This allows the phase cut information to beretrieved. In the depicted configuration, the solid state light source140 includes multiple LEDs connected in series, indicated byrepresentative LEDs 141 to 143.

The rectification circuit 120 provides (dimmed) rectified voltage fromvoltage mains 101. A storage capacitor 820 is used to smooth the DCvoltage to a constant value. Generally, the magnitude of the smoothedand rectified voltage VR depends on the phase cut angle or dimmersetting of the dimmer 105, such that a low phase cut angle correspondingto a lower setting results in a lower rectified voltage and vice versa.In an alternative embodiment, the blocking diode 810 may be omitted andthe degree to which the LEDs 141 to 143 are dimmed directly follows thedependency of the rectified voltage VR and averaged bleeder voltage VBon the phase cut angle. In effect, the least dimming occurs when thedimmer 105 is at a high setting (corresponding to a high phase cutangle), and the most dimming occurs when the dimmer 105 is at a lowsetting (corresponding to a low phase cut angle). Yet, this typicallydoes not lead to a desirable dimming curve as dependency may be far fromlinear. In an embodiment, the first power converter 130 or the radiocircuit 160 measures via (optional) line 800 or phase detection line802, respectively, the phase cut angle and translates the measured phasecut angle in the appropriate LED current ID. To allow proper phase cutangle measurements, the effect of the smoothing capacitor 820 is blockedby the blocking diode 810 from the angle detect point (e.g., option alline 800 or phase detection line 802). In such case, the bleeder voltageVB is a rectified but not averaged voltage that follows the phase cutwaveform, while the rectified voltage VR is a better stabilized supplyvoltage for the first power converter 130 and the second power converter150.

The first power converter 130 is configured to drive the solid statelight source 140 with drive voltage in response to the rectified inputmains voltage from the rectification circuit 120. Generally, the firstpower converter 130 translates the rectified input mains voltage into anappropriate DC drive voltage VD applied to the solid state light source140 to provide a constant drive ID current through the LEDs 141 to 143.For example, the RF controlled lighting unit 110, the first powerconverter 130 or the radio circuit 160, may include a dimmer phase cutangle detection circuit (not shown), to determine or measure values ofthe phase cut angle of the dimmer 105 based on the rectified voltage,enabling the first power converter 130 to provide the appropriate DCdrive voltage. For the purposes of measuring the phase cut angle, thefirst power convertor 130 may include a microcontroller or othercontroller (not shown). Alternatively this task is executed by thesecond power converter 150. That is, in various embodiments, first powerconverter 130 may receive a power control signal from the dimmer phasecut angle detection circuit, which may be a pulse width modulation (PWM)signal that alternates between high and low levels in accordance with aselected duty cycle. For example, the power control signal may have ahigh duty cycle (e.g., 100 percent) corresponding to a maximum on-time(high phase cut angle) of the dimmer 105, and a low duty cycle (e.g., 0percent) corresponding to a minimum on-time (low phase cut angle) of thedimmer 105. When the dimmer 105 is set in between maximum and minimumphase cut angles, the duty cycle of the power control signal is set tospecifically correspond to the detected phase cut angle. The first powerconverter 130 thus converts between the rectified voltage and the DCdrive voltage based on at least the magnitude of the rectified voltageand the value of the power control signal received from the phase cutangle detection circuit. The first power converter 130 may also deliverpower to the radio circuit 160, discussed below, when the dimmer 105 isat an operable dimmer setting (i.e., not at a very low dimmer setting orin the off-state) and/or the electronic is in the on-state (i.e., not inthe off-state).

In various embodiments, the first power converter 130 operates in anopen loop or feed-forward fashion, as described in U.S. Pat. No.7,256,554 to Lys, for example, which is hereby incorporated byreference. However, other types of solid state light source 140 and/orother types of light loads may be included, without departing from thescope of the present teachings. Various techniques for providing the DCdrive voltage and drive current to the solid state light source 140 maybe implemented without departing from the state of the presentteachings.

Both the first power convertor 130 and the second power converter 150are fed by the rectifier 120. In fact, the first and second powerconverters 130 and 150 may be considered connected in parallel. Theblocking diode 810 and capacitor 820 may be considered part of firstpower converter 130. The blocking diode 810 assures that the originalwaveform remains intact to enable precise measurement of the phase cutangle. Moreover, a resistive bleeder circuit 152 of the second powerconverter 150 may be most effective if connected to a rectifiednon-smoothed waveform, thus storage capacitor 820 is particularlyeffective for the first power supply 130, but not for bleeder voltage VBand the second power converter 150. The solid state light source 140 isfed by the first power converter 130.

The second power converter 150 includes the resistive bleeder circuit152 and a power extractor 154. The resistive bleeder circuit 152 isconfigured to apply a resistive load to the input mains voltage from thevoltage mains 101, such that a minimum current flows through thelighting unit 110 even when the solid state light source 140 does notextract sufficient power from the voltage mains 101. This ensures thatthe dimmer 105 and/or the electronic switch 105 a continue to receivepower. Thus, the resistive bleeder circuit 152 assures that the solidstate light source 140 does not give off light when the dimmer 105 is ata very low dimmer setting or in the off-state (and/or the electronicswitch 105 a is in the off-state), e.g., by suppressing voltage swingacross the solid state light source 140.

For example, the resistive bleeder circuit 152 may include a resistancethat is switched into parallel configuration with the solid statelighting load 140 at low currents, to draw extra current along with thesolid state lighting load 140, thus increasing the load to a sufficientminimum for operation of the dimmer 105. When the dimmer 105 is offeringenough power for the solid state light source 140 to give a large amountof light, the radio circuit 160 may also receive power from the firstpower converter 130 (not shown in FIG. 1, but elaborated in FIG. 4,discussed below), since ample power is available, so that the radiocircuit 160 is able to operate at full functionality. However, at lowphase cut angles and/or in an off-state, the radio circuit 160 iseffectively rationed limited power via the second power convertor 150.That is, the radio circuit 160 is generally configured to receive powerfrom the first power convertor 130 when the phase cut angle or theoff-state of the rectified input mains voltage are adequate for fullfunctionality, and to alternatively receive power from the second powerconverter when the phase cut angle or the off-state of the rectifiedinput mains voltage becomes inadequate.

For example, as discussed below with reference to FIG. 4, thecombination from a power combiner (e.g., power combiner 495) of powerfrom the second power converter 150 and/or the first power converter 130may be implemented by two diodes, and a regulator (e.g., on-statecontrol power supply 490) to lower the voltage coming out of the firstpower converter 130. Alternatively, lowering of the voltage may beachieved by tapping current from only the first LED 141 (or first andsecond LEDs 141 and 142) in the solid state light source 140 and a diodetowards the supply voltage pin of the radio circuit 160.

Also, the radio circuit 160 may be further configured to transmit atleast one message to a user when receiving power from the second powerconverter 150. The radio circuit 160 may also reduce energy consumptionwhen only power from the second power convertor 150 is available. Forinstance, reducing energy consumption may include reducing transmitactivity of the transceiver 564 by selectively reducing types ofmessages that are transmitted. For example, in order to reduce energyconsumption, the only type of message that is transmitted may be warningmessages, warning for example that the requested light level can not beachieved with the current phase-cut angle of the rectified input mainsvoltage (implemented by the dimmer 105) and/or state of the electronicswitch 105 a. Such a warning message may be generated or retrieved frommemory by the microprocessor 162, and transmitted by the transceiver 164to a remote control device or other wireless communication device, forexample, where it may be displayed to a user and/or processed by acorresponding processing device to enable formulation of a response.Other types of messages may provide instruction on manually operatingthe dimmer 105 and/or the electronic switch 105 a to attain the desiredlighting level, for example.

The power extractor 154 is connected to the resistive bleeder circuit152 and configured to provide power to the radio circuit 160 (or othercontrol function) when the solid state light source 140 does not extractsufficient power from the voltage mains 101, for example, enabling theradio circuit 160 to receive wireless signals even when the dimmer 105is at a very low dimmer setting or in the off-state (and/or theelectronic switch 105 a is in the off-state). In the depictedconfiguration, the power extractor 154 is connected in series with theresistive bleeder circuit 152 to extract power therefrom, and the radiocircuit 160 is connected in parallel with the power extractor 154,although other configurations may be implemented without departing fromthe scope of the present teachings. Thus, the role of the powerextractor 154 is generally to extract power for the radio circuit 160.The power extractor 154 may also regulate the voltage provided to theradio circuit 160 (if the radio circuit 160 is not doing this itself),as well as support current through the resistive bleeder circuit 152 toensure that the dimmer 105 remains functioning.

The radio circuit 160 includes a transceiver 164 connected to antenna170 for enabling wireless communications with various control sources,such as hand-held remote control devices and various sensors, to receiveinstructions and/or to provide information. That is, the transceiver 164may be configured to receive wireless control signals from a remotecontrol device and to send responsive messages. The transceiver 164 andantenna 170 may also enable wireless communications with the dimmer 105and/or the electronic switch 105 a to wirelessly receive statusinformation (e.g., dimmer settings and on/off states) and output controlsignals to remotely operate the dimmer 105 and/or the electronic switch105 a. In various embodiments, the transceiver 164 may also receive andmeasure control signals from a power line (e.g., mains power line) or asensor and/or communicate electronically with the dimmer 105 and/or theelectronic switch 105 a via the power line (or other physical channel).The sensor may be located anywhere, as long as it has a radiotransmitter and is within radio range of its receiver. The radio circuit160 also includes a microcontroller 162 for processing the receivedstatus information and for determining and generating appropriatecontrol signals in response. The microcontroller 162 is thus configuredto determine and implement responses to the wireless control signalsand/or the measured control signals. For example, the response mayinclude a light output setting (e.g., light level, color, etc.) and/or amessage sent over a radio channel, such as a warning message that thelight level can not be achieved with the current setting of the dimmerand/or state of the electronic switch, as discussed above.

That is, the microcontroller 162 may be configured to determine adesired lighting level of the solid state light source 140 in responseto the wireless control signal, and send a feedback control signal tothe dimmer 105 to cause the dimmer 105 to adjust the input mains voltageto correspond to the determined lighting level and/or to the electronicswitch to switch to an on-state. The microcontroller 162 may send thefeedback control signal to the dimmer 105 and/or the electronic switch105 a wirelessly over a radio channel or over the power line. Forexample, the transceiver 164 of the radio circuit 160 may include afirst transceiver unit for transmitting and/or receiving radio signalsto enable the microcontroller 162 to send the feedback signalwirelessly, and/or a second transceiver unit for transmitting and/orreceive signals by wire to enable the microcontroller 162 to send thefeedback control signal over the power line. In various embodiments, themicrocontroller 162 may change the light level output by the solid statelight source 140 without necessarily communicating with the dimmer 105.For example, if the dimmer setting of the dimmer 105 is high (i.e.,little or no dimming), the microcontroller 162 may cause the first powerconverter 130 to simply reduce the light output by the solid state lightsource 140 without changing the rectified mains voltage. Alternatively,the microcontroller 162 may send a message to the remote control devicevia the transceiver providing instruction on manually operating thedimmer 105 and/or the electronic switch to attain the desired lightinglevel.

In various embodiments, the microcontroller 162 may set the output lightof the solid state light source 140 to a last specified dimming levelpreviously sent via the wireless control signal or the power line, e.g.,whichever signal changed last. Similarly, the microcontroller 162 mayset the solid state light source 140 to output light at a lowestspecified dimming level previously sent via the power line or thewireless control signal, e.g., whichever signal demands the lowestsetting. 25. Also, the microcontroller 162 may set the solid state lightsource to output light based on a look-up table (not shown), forexample, received from the wireless remote control device. A measuredphase cut angle may be input to the look-up table and a correspondingdesired light setting may be output from the lookup table.

FIG. 2 is a block diagram showing a power extractor of the RF controlledlighting system of FIG. 1, according to a representative embodiment. Inthe depicted embodiment, the configuration of the power extractor iseffectively independent of the resistive bleeder circuit, and thereforethe power extractor operates as described regardless of the type ofresistive bleeder circuit may be in place (examples of which arediscussed below with reference to FIGS. 3A to 3D.

Referring to FIG. 2, power extractor 154 includes a capacitor 255connected between voltage Vcc and a ground voltage, and a Zener diode256 connected in parallel with the capacitor 255. A cathode of the Zenerdiode 256 is connected to the voltage Vcc and an anode of the Zenerdiode is connected to the ground voltage. The Zener diode 256 ensuresthat bleeder leakage current can still flow when the capacitor 255 isfully charged. This improves the operation of the dimmer 105 and/or theelectronic switch when the radio circuit 160 extracts only a smallamount of power or a low current. The capacitor 255 needs to be largeenough to allow being charged only during small fractions of the 50Hz/60 Hz cycle of the mains 101 when the dimmer 105 allows current toflow. Also the radio circuit 160 may draw large peak currents during afew milliseconds of transmission, which should not discharge thecapacitor 255 too much. The voltage Vcc connection provides a powersupply for the radio circuit 160, which is connected in parallel withthe power extractor 154 via terminals 257 (Vcc connection) and 258(ground connection). In an embodiment, the power extractor 154 mayfurther include a voltage regulator (not shown) configured to stabilizethe voltage Vcc provided to the radio circuit 160 from the powerextractor 154. The voltage regulator is discussed further below withreference to FIG. 5.

FIGS. 3A to 3E are block diagrams showing second power convertors of theRF controlled lighting system of FIG. 1, including different resistivebleeder circuits used in conjunction with the power extractor, accordingto representative embodiments.

Referring to FIG. 3A, second power converter 150-1 includes resistivebleeder circuit 152-1 and the power extractor 154. The resistive bleedercircuit 152-1 simply includes a bleeder resistor 351. The powerextractor 154 is configured as described above with reference to FIG. 2,and therefore the description will not be repeated. Terminals 151 and152 arranged to the left of the second power converter 150-1 to connectthe second power converter 150-1 (that is, the series combination of theresistive bleeder circuit 152-1 and the power extractor 154) in parallelwith each of the first power converter 130 and the solid state lightsource 140. Of course, in alternative configurations, the solid statelight source 140 may be connected on the right side of the second powerconverter 150-1, as long as the solid state light source 140 and thesecond power converter 150-1 are arranged in parallel with one another.The terminals 257 and 258 arranged to the right of the second powerconverter 150-1 to connect the power extractor in parallel with theradio circuit 160, enabling the radio circuit 160 to receive voltageVcc, as discussed above.

Referring to FIG. 3B, second power converter 150-2 includes resistivebleeder circuit 152-2 and the power extractor 154. The resistive bleedercircuit 152-2 includes a bleeder resistor 352 and a bleeder capacitor353 connected in series. Terminals 151 and 152 connect the second powerconverter 150-1 in parallel with each of the first power converter 130and the solid state light source 140, and the terminals 257 and 258connect the power extractor 154 in parallel with the radio circuit 160,as discussed above.

Referring to FIG. 3C, second power converter 150-3 includes resistivebleeder circuit 152-3 and the power extractor 154. The resistive bleedercircuit 152-3 includes a current source configured to provide asubstantially constant bleeder current I_(B). In the depicted example,the current source is implemented by bi-polar junction transistor (BJT)355. The BJT 355 includes a collector connected to terminal 151, anemitter connected to terminal 257 (at the power extractor 154) viaemitter resistor 356, and a base connected to the terminal 151 via abase resistor 358 and connected to the terminal 257 via a Zener diode359. The substantially constant current I_(B) is approximately equal tothe difference between a voltage Vz across the bleeder Zener diode 359and a base-emitter voltage Vbe of the BJT 355, divided by a resistancevalue R of the emitter resistor 356 (that is, I_(B)=(Vz−Vbe)/R).Terminals 151 and 152 connect the second power converter 150-1 inparallel with each of the first power converter 130 and the solid statelight source 140, and the terminals 257 and 258 connect the powerextractor 154 in parallel with the radio circuit 160, as discussedabove.

Referring to FIG. 3D, second power converter 150-4 includes resistivebleeder circuit 152-4 and the power extractor 154. The resistive bleedercircuit 152-4 is an example of a more complex resistive bleeder circuit,as described for example in U.S. Patent App. Pub. No. 2006/0192502 toBrown et al. (published Aug. 31, 2006), which is hereby incorporated byreference. In particular, similar to FIG. 2 of Brown et al., theresistive bleeder circuit 152-4 includes a firstmetal-oxide-semiconductor field-effect transistor (MOSFET) 361 having afirst gate, a first drain and a first source, and a second MOSFET 362having a second gate, a second drain and a second source. The seconddrain of the second MOSFET 362 is connected to terminal 151 via resistor377. The second source of the second MOSFET 362 is connected to terminal257 (and thus the power extractor 154). The second base is connected tothe first drain of the first MOSFET 361 at node 341 via resistor 376. Inaddition, resistor 374 is connected between node 341 and terminal 151;resistor 375 is connected between node 341 and terminal 257; diode 380is connected between node 341 and resistor 375; and Zener diode 383 isconnected between node 341 and terminal 257.

The first source of the first MOSFET 361 is connected to terminal 257,and the first gate of the first MOSFET 361 is connected to node 342 viaresistor 373. In addition, resistor 372 and Zener diode 381 areconnected between node 342 and terminal 151; resistor 371 is connectedbetween node 341 and terminal 257; and Zener diode 382 is connectedbetween node 342 and terminal 257.

The resistor/Zenor diode circuit comprising resistors 371, 372 and theZener diode 381 is configured to determine a magnitude of the rectifiedinput mains voltage to be applied to the first gate of the first MOSFET371. The second MOSFET 372 is configured to receive at the second gatean inverted output from the first drain of the first MOSFET 371, wherethe second MOSFET 372 is ON even when the adjusted input mains voltagepasses through zero. The resistor 377 connected to the second drain ofthe second MOSFET 372 is configured to determine the magnitude of theresistive load applied to the dimmer 105. In this configuration, theresistive bleeder circuit 152-4 may be activated, for example, during atime period when power applied to the resistive bleeder circuit 152-4 bythe voltage mains 101 is substantially between +10 volts and zero voltsand between −10 volts and zero volts. Terminals 151 and 152 connect thesecond power converter 150-4 in parallel with each of the first powerconverter 130 and the solid state light source 140, and the terminals257 and 258 connect the power extractor 154 in parallel with the radiocircuit 160, as discussed above.

Referring to FIG. 3E, second power converter 150-5 includes resistivebleeder circuit 152-5 and the power extractor 154 integrated with theresistive bleeder circuit 152-5. In particular, the resistive bleedercircuit 152-5 is similar to the resistive bleeder circuit 152-4,discussed above, except that the circuitry of the power extractor 154 isincorporated within the circuitry of resistive bleeder circuit 152-5,which is otherwise substantially the same as the resistive bleedercircuit 152-4 (e.g., corresponding to FIG. 2 in U.S. Patent App. Pub.No. 2006/0192502).

The configuration differs from the previously discussed second powerconverters 150-1 to 150-4, in which the resistive bleeder circuit andthe power extractor are essentially independent from one another and canbe arranged in various combinations, in that power in the second powerconverter 150-5 is extracted in current from of the second emitter ofthe second MOSFET 372 (i.e., the main power transistor). The resistivebleeder circuit 152-5 has an extra output (terminals 257 and 258) thatfeeds power into the radio circuit 160. In the depicted configuration,the wire carrying the bleeder main current from the second source of thesecond MOSFET 372 is interrupted for insertion of the power extractor154 (the Zener diode 256 in parallel with the capacitor 255).

In an illustrative embodiment, the capacitor 255 may have a value ofabout 47 microfarads (g) and the Zener diode 256 may have a Zenervoltage value of about 3.3 volts or 5 volts, for example. As mentionedabove, the Zener diode 256 is connected across Vcc (terminal 257) andground (terminal 258) to ensure that the bleeder leakage current canstill flow when the capacitor 255 is fully charged. A useful extensionis to choose the Zener voltage value slightly higher, e.g., about 9volts to about 12 volts, and to add a voltage regulator, such as a knownlinear regulator IC, such as Voltage Regulator IC 7805 available fromFairchild Semiconductor®, to stabilize the voltage Vcc offered to theradio circuit 160.

The current in the second MOSFET 372 has only one “ear” (i.e., a briefperiod of large current) on the right side of (i.e., immediatelyfollowing) the mains zero crossing when the dimmer 105 is on. The secondMOSFET 372 is fully turned on when the mains voltage rises above 30V,for example, while the first MOSFET 371 is not yet active. The secondMOSFET 372 is turned off at about 70V. The second gate of the secondMOSFET 372 is essentially floating at mains zero crossings due toparasitic capacitances of the first and second MOSFETs 371 and 372 anddiode blocking reverse current. Therefore, the current in the secondMOSFET 372 already starts to flow when the mains voltage is above a fewvolts (e.g., more than about 10 volts). Of course, in variousalternative configurations, the sources and drains of the MOSFETtransistors may be switched, or other types of transistors, includingBJTs and other types of FETs, may be incorporated without departing fromthe scope of the present teachings. Also, component values may beincorporated without departing from the scope of the present teachings.

Under some circumstances, power extracted from a resistive bleedercircuit may not be enough to supply the radio circuit (e.g., the radioIC) and other functions when the lighting unit is on. FIG. 4 is a blockdiagram showing an RF controlled lighting system, in which powersupplied from a resistive bleeder circuit is combined with power fromanother power supply, according to a representative embodiment.

Referring to FIG. 4, RF controlled lighting system 400 includes dimmer105 and RF controlled lighting unit 410 (lamp), where the dimmer 105 isconfigured to adjust a phase cut angle of an unrectified input mainsvoltage from voltage mains 101 in accordance with an adjustable dimminglevel. The RF controlled light unit 410 includes rectification circuit120, first power converter 130, second power converter 150, and radiocircuit 160, which are substantially the same as discussed above withreference to FIGS. 1 to 3D, and therefore the corresponding descriptionswill not be repeated. For example, the second power converter 150(resistive bleeder circuit with power extractor) may be implemented asany one of the above embodiments, second power converter 150-1 to 150-5.The RF controlled light unit 410 also includes on-state control powersupply 490, power combiner 495, and a solid state light source 440,which includes representative LEDS 441 to 445. The power to the LEDS 441to 445 go through blocking diode 810 followed by storage capacitor 820,and the further driver electronics of the first power convertor 130. Inthe depicted embodiment, the input to the on-state control power supply490 is over some of the lower LEDs (e.g., LEDs 444 and 445) in the LEDstring of the solid state light source 440. Alternatively, the input tothe on-state control power supply 490 may be before the blocking diode810, behind the blocking diode 810, or behind the first power convertor130, without departing from the spirit of the present teachings. Theon-state control power supply 490 is optimized for operation duringnormal on-state or during a modest degree of phase cut dimming by thedimmer.

As shown in FIG. 4, the power combiner 495 includes first and seconddiodes D1 and D2 configured to take the power from a first supply (e.g.,second power converter 150) or second supply (e.g., first powerconverter 130 and/or solid state light source 440), whichever deliversthe highest voltage. As shown, the first diode D1 is arranged to conductin a direction from the second power converter 150 towards the radiocircuit 160, and the second diode D2 is arranged to conduct in adirection from the on-state control power supply 490 towards the radiocircuit 160. Alternatively, the functionality of the first and seconddiodes D1 and D2 may be implemented by one or more transistors that areactively switched. The on-state power supply 490 reduces to “stealing”some current from the solid state light source 440.

The regulation of the supply voltage occurs implicitly because thevoltage across the LEDs 441 to 445 is approximately 3 Volts regardlessof the current through the LEDs 441 to 445. The power combiner 495 isconfigured to combine power extracted from the resistive bleeder circuit152 by the power extractor 154 in the second power converter 150 andpower provided by the on-state control power supply 490. In anembodiment, the ratio of the combination varies depending on the powerdemand. For example, in an embodiment, the power output by the powercombiner 495 may be taken entirely from the second power converter 150when sufficient, while the power from the on-state control power supply490 may be incrementally added as demand requires. Essentially, thefirst and second diodes D1 and D2 in the power combiner 495 ensure thatthe radio circuit 160 is powered from the relatively high-power firstpower converter 130, and only extracts a small amount of power from thesecond power converter 150 when the solid state light source 440 is(almost) fully off. This allows the radio circuit 160 to operate duringon-states and off-states. In an embodiment, the power combiner 495 maybe integrated into the radio circuit 160.

FIG. 5 is a block diagram showing an RF controlled lighting system,according to another representative embodiment.

Referring to FIG. 5, RF controlled light unit 510 receives unrectifiedvoltage from the voltage mains 101 (not shown in FIG. 5), which may bedimmed or undimmed. The RF controlled light unit 510 includesrectification circuit 520, first power converter (LED driver) 530, solidstate light source 540, second power converter 550, power monitor 580,phase cut angle detector 590, and radio circuit 560. The radio circuit560 may be a radio IC, for example, and includes microcontroller 562 andtransceiver 564, connected to antenna 570. The rectification circuit520, the first power converter 530, the solid state light source 540,the second power converter 550, the radio circuit 560 and the antenna570 may be substantially the same as the rectification circuit 120, thefirst power converter 130, the solid state light source 140, the secondpower converter 150, the radio circuit 160, and the antenna 170,respectively, discussed above with reference to FIGS. 1 to 3E, and thefollowing description will be directed to differences between theseelements. For example, the resistive bleeder circuit of the second powerconverter 550 may be implemented substantially the same as any of theresistive bleeder circuits 152-1 to 152-5, although for purposes ofillustration, resistive bleeder circuit 152-2 is depicted.

Likewise, the power extractor 554 may be substantially the same as thepower extractor 154 discussed above with reference to FIG. 2, exceptthat it may include optional voltage regulator 558. The voltageregulator 558 stabilizes the voltage Vcc provided to the radio circuit560. The voltage regulator 558 may be used when fluctuations across thecapacitor 255 are too large, e.g., if the microcontroller 562 drains thecapacitor 255 when transmitting. The output of the voltage regulator 558is merged with power from a second supply by means of first and seconddiodes D1 and D2, which in essence perform the function of powercombiner 495. However, in alternative configurations, the powerextractor 554 may be replaced by a diode or a wire connection(input=output), such that the regulators (if present) and the diodesjointly form the power combiner 495. A practical embodiment of aregulator circuit usually already performs the function of a diode, suchthat if a regulator is present, the corresponding diode may be omitted.The power extractor 554 is configured to deliver power to the radiocircuit 560, including the microcontroller 562, via Vcc and ground(respectively corresponding to terminals 257 and 258 in FIG. 2). Asecond voltage regulator 570 may be included to ensure that the voltageextracted from first power converter 530 is suitable for themicrocontroller 562. Here, ground is a local reference ground in the RFcontrolled lighting unit 510 (and thus not galvanically the same as aneutral wire coming from the voltage mains 101).

The microcontroller 562 in the radio circuit 560 is configured to detectthe phase cut angle of the dimmer 105 (not shown). To this end, themicrocontroller 562 includes means for sampling the mains voltage. Forexample, the microcontroller 562 may observe voltage after the rectifier520. To allow proper measurements, the rectified mains voltage is notsmoothed by a capacitor. However, when the first power converter 530prefers some particular capacitance, a diode (not shown) may be placedbetween the rectifier 520 and the first power converter 530, and acapacitor (not shown) may be placed behind this diode.

As shown in the embodiment of FIG. 5, the phase cut angle detector 590includes a voltage divider, indicated by resistors 591 and 592. Thephase cut angle detector 590 reduces the voltage level of the rectifiedmains voltage to a voltage level that can be handled by input IN1 forthe microcontroller 562 for phase cut angle detection. In an embodiment,the phase angle detector 590 and/or the microcontroller 562 may beconfigured to detect the phase cut angle by sampling digital pulsescorresponding to waveforms of the rectified input mains voltage andmeasuring consecutive half cycles based on lengths of the sampleddigital pulses.

The input IN1 may be a digital input, in which case the microcontroller562 calculates a fraction of time that the mains voltage is non-zero(e.g., above a predetermined threshold). This corresponds to thefraction of time that the mains cycle is non-interrupted, which can betranslated to a phase cut angle of the mains voltage (by operation ofthe dimmer 105). Also, when the input IN1 is operated as a digitalinput, the resistor 591 may be about 1 Mohm between the rectified mainsvoltage and the input IN1, and the resistor 592 may be about 100 Kohmbetween the input IN1 and ground, for example. Alternatively, the inputIN1 may be an analog input, in which case the microcontroller 562 isable to monitor the sinusoidal shape of the rectified mains voltageduring the conducting time of the dimmer 105.

The power monitor 580 likewise includes a voltage divider, indicated byresistors 581 and 582, that reduces a voltage level of voltage output bythe resistive bleeder circuit 552 that can be handled by input IN2 ofthe microcontroller 562. The voltage divider is needed since voltage atthe capacitor 555 of the power extractor 554 is higher than theregulated voltage Vcc. Based on the output of the power monitor 580, themicrocontroller 562 is able to monitor whether the power extractor 554is able to deliver enough power to supply the radio circuit 560. Whenthe voltage level at the input IN2 is too low, the radio circuit 560 maydecide not to transmit, to delay a transmission until more power hasbeen aggregated, or put the transceiver (or the receiver) in sleep mode.These actions prevent voltage Vcc from dropping too low, which wouldnecessitate a time-out and rebooting of the radio circuit 560 oncesufficient power is restored.

Alternatively, the input IN2 may be an analog input, in which case theradio circuit 560 must include an analog-to-digital converter (ADC).Also, alternatively, the voltage level at the input IN2 may be comparedto a threshold voltage (e.g., internally in the radio circuit 560). Whenthe voltage level at the input IN2 is below the threshold voltage, theradio circuit 560 takes actions to reduce power consumption, such asduty cycling the receiver, refraining from or delay transmission, etc.This may be done under control of the microprocessor 562.

In various embodiments, the microprocessor 162, 562 may be implementedusing one or more processing devices, such as a computer, a processor, amicroprocessor, a digital signal processor (DSP), one or moreapplication specific integrated circuits (ASICs), one or more FPGAs, orcombinations thereof, using software, firmware, hard-wired logiccircuits, or combinations thereof. The microprocessor may have access tomemory (not shown), comprising a non-transitory computer readable mediumfor storing operating software, modules, data and algorithms forexecuting the various embodiments described herein, including spectraldetermination and/or analysis of the analyte(s) of interest. Examples ofa computer readable medium include various types of nonvolatile readonly memory (ROM) and volatile random access memory (RAM), such aserasable programmable ROM (EPROM), electrically erasable programmableROM (EEPROM), static RAM (SRAM), dynamic RAM (DRAM), a DVD, a universalserial bus (USB) drive, and the like, although implementations of themicroprocessor and/or the computer readable media may vary withoutdeparting from the scope of the present teachings.

Referring again to FIG. 1, for purposes of illustration, the radiocircuit 160 may be configured to implement various features in responseto control signals and/or other input provided for example by remotecontrol devices and/or sensors. For example, if a user attempts toswitch on the RF controlled lighting unit 110 via a radio signal, whilethe dimmer 105 is in a fully dimmed or off-state (or while theelectronic switch is in an off-state), the RF controlled lighting unit110 responds with a message, generated or retrieved from memory by themicroprocessor 162 and transmitted by the transceiver 164, to the effectthat it is behind a dimmer and/or an electronic switch and cannot getenough power to perform the command provided by the radio signal. Asanother example, if the user attempts to switch on the RF controlledlighting unit 110 via a radio signal, while the dimmer 105 is in a fullydimmed or off-state (or while the electronic switch is in an off-state),the RF controlled lighting unit 110 sends a control signal to the dimmerand/or the electronic switch dimmer to transition out of the off-state(into the on-state). This control signal may be sent over a radiochannel between the RF controlled lighting unit 110 and the dimmer 105and/or the electronic switch, or this control signal may be sent overthe power line from the RF controlled lighting unit 110 to the dimmer105 and/or the electronic switch.

When the remote control device is using an application (“app”), theremay be a fall back to app overrule, for example. That is, if a userwants to use an app to overrule the light setting provide by the dimmer105, the user can do so. However, when dimmer phase cut angle is at avery low value (too low to give the RF controlled lighting unit 110enough power) or in an off-state, the RF controlled lighting unit 110sends a warning to the app. The app shows this on the screen “Dear homeuser, the setting that you like to control via this app can not berealized with the current dimmer setting. Please put the dimmer in fullposition.” In other words, a message may be provided to the remotecontrol device via from the microprocessor 162 via the transceiver 164providing instruction on manually operating the dimmer 105 to attain thedesired lighting.

Although much of the above description is generally directed to use of alegacy phase dimmer with manual control, it applies equally to dimmersthat are equipped with a radio receiver. In this case, additionalfeatures may be implemented. For example, if the RF controlled lightingunit 110 receives a control command via its radio interface (e.g., radiocircuit 160), but cannot execute this command because the dimmer 105and/or electronic switch delivers too little power, then the RFcontrolled lighting unit 110 may send a control signal to the dimmer 105and/or the electronic switch requiring it to change the phase cut angleor to transition from the off-state to the on-state.

A presence detector in the RF controlled lighting unit 110 that is ableto detect presence during periods that the dimmer 105 and/or theelectronic switch is in off-state. When a motion/new presence isdetected by the presence detector, the radio circuit 160 will send acommand message to the (wall) dimmer 105 and/or the (wall) electronicswitch to the on-state.

FIG. 6 is a flow diagram showing a process of operating an RF controlledlighting system, according to a representative embodiment. The processmay be implemented, for example, by firmware and/or software executed bythe radio circuit 160, 560 shown in FIGS. 1 and 5.

Referring to FIG. 6, a method is provided for remotely controlling alighting unit (e.g., RF controlled lighting unit 110) configured forconnection to a dimmer configured to adjust a phase cut angle of aninput mains voltage. Of course, substantially the same method may beapplied to controlling an electronic switch (or a dimmer) with respectto switching between an on-state and an off-state, but not necessarilyadjusting dimming levels. In block S611, a resistive bleeder circuit isconnected in parallel with a solid state light source of the lightingunit, such as a light emitting diode (LED) light source. The resistivebleeder circuit applies resistive load to the dimmer when the inputmains voltage becomes inadequate to drive the LED light source due tothe phase-cut angle or the off-state of the input mains voltage. Poweris extracted from the resistive bleeder circuit in block S612 forpowering to a radio circuit (e.g., radio IC) when the resistive bleedercircuit is connected in parallel with the LED light source.

In block S613, a lighting control signal is received wirelessly, e.g.,from a remote control device (or other controlling device), as discussedabove, by the radio circuit when the radio circuit is powered by thepower extracted from the resistive bleeder circuit. The lighting controlsignal may indicate a desired lighting level of the LED light source, ormay indicate a desire to turn the LED light source from an off-state toan on-state. In response, it is determined in block S614 whether thelighting command indicated by the lighting control signal is possible tobe performed given the present state of the RF controlled lighting unit.For example, it is determined whether the RF controlled lighting unit isin a highly dimmed or off-state, thus preventing execution of thelighting control signal.

When the lighting command cannot be performed (block S614: No), amessage may be sent wirelessly in block S615 to the remote controldevice stating that the desired lighting level is not attainable becausethe LED light source is not receiving sufficient power, e.g., at acurrent phase cut angle of the input mains voltage or is in theoff-state. In block S616, another message may be sent wirelessly to theremote control device providing instruction on manually adjusting thephase cut angle of the input mains voltage (or on switching to theon-state) to attain the desired lighting level.

When the lighting command can be performed (block S614: Yes), a feedbackcontrol signal is generated and sent from the radio circuit to thedimmer (or to the electronic switch) in block S617 for adjusting thephase cut angle of the input mains voltage (or for turning on theelectronic switch) to achieve the desired lighting level, as indicatedby the feedback signal. The feedback control signal may be sentwirelessly to the dimmer over a radio channel, or it may be sent over awired power line. The LED light source may be adjusted to emit thedesired lighting level indicated by the feedback control signal.Alternatively, the LED light source may be adjusted to emit the lesserof the desired lighting level indicated by the feedback control signalor a current phase cut angle of the input mains voltage, or the LEDlight source may be adjusted to emit the more recent of the desiredlighting level indicated by the feedback control signal or an adjustmentof the current phase cut angle of the input mains voltage.

The feedback control signal may include a dedicated command indicatingwhether the LED light source should be adjusted following a dimmersetting of the dimmer or not following the dimmer setting of the dimmer.The dedicated command indicates that the LED light source should beadjusted following the dimmer setting of the dimmer when the phase cutangle does not allow LED light source to emit the desired lighting levelindicated by the feedback control signal.

While multiple embodiments have been described and illustrated herein,those skilled in the art will readily envision a variety of other meansand/or structures for performing the function and/or obtaining theresults and/or one or more of the advantages described herein, and eachof such variations and/or modifications is deemed to be within the scopeof the inventive embodiments described herein. More generally, thoseskilled in the art will readily appreciate that all parameters,dimensions, materials, and configurations described herein are meant tobe exemplary and that the actual parameters, dimensions, materials,and/or configurations will depend upon the specific application orapplications for which the inventive teachings is/are used.

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, many equivalents to the specificinventive embodiments described herein. It is, therefore, to beunderstood that the foregoing embodiments are presented by way ofexample only and that, within the scope of the appended claims andequivalents thereto, inventive embodiments may be practiced otherwisethan as specifically described and claimed. Inventive embodiments of thepresent disclosure are directed to each individual feature, system,article, material, kit, and/or method described herein. In addition, anycombination of two or more such features, systems, articles, materials,kits, and/or methods, if such features, systems, articles, materials,kits, and/or methods are not mutually inconsistent, is included withinthe inventive scope of the present disclosure.

For example, it may be understood that communications via radio asdescribed above may also occur via various alternative means, such asinfrared, visual light communication, ultrasound communication or viapower line communication. When power line communication is used incombination with phase cut dimming or electronic switching, for example,it may be the case that high-frequency power line signals are notinterrupted by the phase cut dimmer. One main difference betweenalternative communication means and radio communication, as in theembodiments discussed above, is that the communication interface (e.g.,transceiver 164) is not connected to an antenna 170, but is connected toan ultrasound communication or an infrared IR photo diode, for example,or is connected to probe the mains for power line communication signals.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e., “one or more” ofthe elements so conjoined. Other elements may optionally be presentother than the elements specifically identified by the “and/or” clause,whether related or unrelated to those elements specifically identified.Thus, as a non-limiting example, a reference to “A and/or B”, when usedin conjunction with open-ended language such as “comprising” can refer,in one embodiment, to A only (optionally including elements other thanB); in another embodiment, to B only (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of,” or, when usedin the claims, “consisting of,” will refer to the inclusion of exactlyone element of a number or list of elements. In general, the term “or”as used herein shall only be interpreted as indicating exclusivealternatives (i.e. “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of” “Consisting essentially of,” when used in the claims,shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example, “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one, A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

It should also be understood that, unless clearly indicated to thecontrary, in any methods claimed herein that include more than one stepor act, the order of the steps or acts of the method is not necessarilylimited to the order in which the steps or acts of the method arerecited.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” “composed of,” and the like are tobe understood to be open-ended, i.e., to mean including but not limitedto. Only the transitional phrases “consisting of” and “consistingessentially of” shall be closed or semi-closed transitional phrases,respectively, as set forth in the United States Patent Office Manual ofPatent Examining Procedures, Section 2111.03.

The invention claimed is:
 1. A radio frequency (RF) controlled lightingunit suitable for connection to at least one of a dimmer configured toadjust a phase cut angle of an input mains voltage from mains inaccordance with an adjustable dimming level or an electronic switchconfigured to provide selection between an on-state and an off-state,the lighting unit comprising: a solid state light source; a radiocircuit configured to receive a wireless control signal, enablingcontrol of the lighting unit; a rectifier circuit configured to rectifythe input mains voltage received from the dimmer or the electronicswitch; a first power converter configured to drive the solid statelight source in response to the rectified input mains voltage and todeliver power to the radio circuit; and a second power convertorconfigured to deliver power to the radio circuit when the rectifiedinput mains voltage becomes inadequate for the first power converter dueto the phase-cut angle of the rectified input mains voltage or theoff-state of the electronic switch, wherein the second power convertoris connected in parallel with the first power converter.
 2. The lightingunit of claim 1, wherein the second power convertor comprises: aresistive bleeder circuit configured to apply a resistive load to theinput mains voltage such that a minimum current flows through thelighting unit even when the solid state light source does not extractsufficient power from the mains, ensuring that the solid state lightsource does not give off light due to the phase-cut angle of therectified input mains voltage or the off-state of the electronic switch;and a power extractor connected to the resistive bleeder circuit andconfigured to provide the power to the radio circuit when the solidstate light source does not extract sufficient power from the mains,enabling the radio circuit to receive the wireless signal.
 3. Thelighting unit of claim 2, wherein the power extractor is connected inseries with the resistive bleeder circuit.
 4. The lighting unit of claim3, wherein the power extractor comprises: a capacitor connected betweena voltage Vcc and a ground voltage; and a Zener diode connected inparallel with the capacitor.
 5. The lighting unit of claim 4, whereinthe power extractor further comprises: a voltage regulator configured tostabilize the voltage Vcc provided to the radio circuit.
 6. The lightingunit of claim 2, wherein the resistive bleeder circuit comprises ableeder resistor.
 7. The lighting unit of claim 6, wherein the resistivebleeder circuit further comprises a bleeder capacitor connected inseries with the bleeder resistor.
 8. The lighting unit of claim 2,wherein the resistive bleeder circuit comprises a current sourceconfigured to provide a substantially constant current, the currentsource comprising: a bleeder transistor; an emitter resistor connectedto an emitter of the bleeder transistor; a base resistor connected to abase of the bleeder transistor; and a bleeder Zener diode connectedbetween the base of the bleeder transistor and the Vcc voltage.